One of the points that frequently comes up, in the case of music and lyrics is protecting someone who developes a new arrangement to music that is in the public domain. Groups like the Weavers and Steel Eye Span copyright their improvements/arrangements to the work in question, to preserve their rights to it and any revenues generated by others utilizing their material. The Weavers copyrighted their materials under the name of Paul Campbell, while Steel Eye Span seems to have used their band's name. This practice is common in music, and requires "marked changes" be made to the older work in order to gain your own copyright. Just how much is judged to be a marked difference is a murky point and up for argument. Similar cases hold for patents, and the "inventer" of the waterbed justifyably credited Robert A. Heinlein with its genesis, saysing that he merely put Heinlein's ideas into practical use.


Dave